1. Field of the Invention
The present invention relates to a display device, and more particularly to a display device that is adapted to selectively display a normal image, a stereoscopic image and a multi-view image.
2. Discussion of the Related Art
Nowadays, as the standard of living rapidly improves, there is an increasing demand for the diversification of functions of the electronic equipment that is used. In particular, display devices that display images are required to have a stereoscopic image function in which the display device displays 3D-images, or to have a multi-view function in which another image is displayed with a different viewing angle on one screen. The stereoscopic image function or the multi-view function is widely required in a variety of fields, such as advertising, educational training, entertainment, and navigations.
In order to provide the stereoscopic image function or the multi-view function to the display device, the display device includes a display panel displaying images, and a barrier that divides the image provided at the display panel into at least first and second images.
The display panel might be a liquid crystal panel that can be made light and thin and of which the power consumption is low. The liquid crystal panel includes first and second substrates, a liquid crystal layer interposed between the two substrates, and a polarizer that is adhered to the outer side surface of at least one of the first and second substrates.
The barrier includes a light shielding part that intercepts light and a light transmission part through which light is transmitted. However, when using the barrier, there is a disadvantage in that only the stereoscopic image or the multi-view image can be displayed.
For the implementation of a display device capable of selectively displaying the normal images and one of the stereoscopic images and multi-view images, a technique has been developed that replaces the barrier by a liquid crystal lens which makes changes to a refractive index in accordance with an electric field.
The liquid crystal lens includes first and second substrates and a liquid crystal interposed between the two substrates. The first and second substrates each include first and second electrodes.
Such a liquid crystal lens is tilted at a fixed angle with respect to the vertical direction of the liquid crystal panel, in order to display the multi-view image. Due to this, the optical axis of the polarizer of the liquid crystal panel might be greatly different from the axis of the light passing through the liquid crystal lens. As the difference between the optical axis of the polarizer and the optical axis of the liquid crystal lens becomes larger, cross-talk might be generated, and the picture quality may also be deteriorated.
Moreover, there is another disadvantage in that the picture quality of the stereoscopic image or the dual-view image might be deteriorated further because the optical axis of the liquid crystal lens and the optical axis of the liquid crystal panel become different from each other according to the alignment direction of the liquid crystal lens.
As a result, it is possible to selectively display the normal images and one of the stereoscopic images, the multi-view images, and the stereoscopic multi-view images by use of the liquid crystal lens. However, a problem is generated in that the picture quality thereof is deteriorated by the optical property of the liquid crystal lens.